Most Sunday afternoons, Glenn Newman hosts church in his living room. It’s much cozier than a typical religious space, with stuffed leather recliners and gas logs glowing in the fireplace. More a grandparent’s den than a sanctuary.

A half-dozen attendees watch a sermon from a California pastor and follow along with a study guide. Afterward, they make small talk between bites of homemade nachos and chocolate cake prepared by Newman’s next-door neighbors. 

Quietly, over the…